Gas Piping Question

I am getting different answers on this one in the field and I'd like a
little help.
I need to supply gas to a new hybrid water heater. According to the
manufacturer, it requires a 3/4" input line.
The gas line comes directly from the gas meter via a 1" line to the water
heater closet. There, it goes into a Tee. The Tee is a 1" (from the meter),
3/4" that feeds the rest of the house (furnace and stove), and 1/2" that
feeds the existing water heater. Some say I have to remove the Tee and go
with one that gives me a 3/4" line to the rest of the house and a 3/4" line
to the water heater. Others say I can just put a bushing on the 1/2" line,
taking it up to 3/4" and I'll be fine.
I've tried talking to the manufacturer and they do not want to get involved
in "construction matters" (liability worries).
This is in California (1/4 pound pressure gas).
Any thoughts? Go with a new tee or bush up the old one? Or any other idea?
Thanks
Tim

Under the bush-up logic, you could have a 3/4" line come into the
house and bush up to a 1" and have it be the equivalent of a 1" line.
I don't believe that is quite the way it works. With the smaller pipe
you have a restriction, which is the limiting factor.
I am surprised that the manufacturer didn't give more guidance on
this. The normal manufacturer response in such a situation is along
the lines of "you need 3/4" so use 3/4" for the supply line, not just
part of it."
R

To properly answer this question, you need to tell us:
The length of the 1" pipe from the meter to this Tee.
The length of the pipe run from this Tee to the new water heater.
The demand of the other appliances (the furnace and stove).
Basically, in designing gas piping systems, you are allowed 0.5"
w.c. pressure drop from the regulator to the outlet. Using a 1/2"
port on the tee with a 3/4" bushing will cause more pressure drop than
using a 3/4" tee would. Depending on the pressure drop in the rest of
the system, this may or may not be acceptable.
Cheers, Wayne

Agreed, T in at 3/4" point. If it makes it more convenient you could
replace some of the 1/2" with 3/4" and T in further down. T'ing into
the 1/2" could create flow problems for the other appliances. I would
not do that. As another poster pointed out there are formula for
calculating the pipe size based on the demand of each appliance and
the length of pipe.

Really nothing I guess.
We are not plumbers. We are doing this as part of a huge remodel. We can't
use "unions" as such and we know we have to use a left/right connection.
Personally, I have had bad luck with right/lefts over the years. It always
seems like one side is too loose when the other is tight. I get tired of
fighting it. I always make sure both sides start at the same time and all
that, but it seems like it just never goes on cleanly. It was just me trying
to get something done easily and without a problem.

I believe most general contractors are pretty much the same. We all came
into this doing something like electrical or tile or carpentry or something
else and we get licensed to be able to do it all so we don't have to bring
in someone who may or may not be more qualified. The fact that we do not
know EVERYTHING about a given topic doesn't necessarily mean we are not
qualified. We could debate the "is the general contractor REALLY qualified
to do everything?" question for 100 years.

A general contractor is not licensed to "do it all" in any jurisdiction
I know. And just because someone can build a perfect foundation or set
the most fabulous tile job doesn't mean they understand gas piping or
whatever else. That doesn't diminish them and there really is no debate.
Just consider your present situation. You say "someone said this" and
"someone said that" and then pose the question in a newsgroup where your
only hope is to get more "someone said this" and "someone said that"
responses. Will you decide by tallying up the responses?
My buddy had a log home built about five years ago and hired a gc who is
very skilled but thinks he can do everything. The foundation elevation
is perfect, the foundation is dead on square and level and the logs and
beams are installed perfectly. But my buddy is having constant issues
with the heating system, aerator pump and electrical system because the
job looks good but the guy didn't understand the fine points of what he
was doing.

Here in the left coast, as a GC, I can do everything except fire sprinklers
and well digging. The interesting thing for me is that I cannot sell myself
as a plumber, let's say, UNLESS I am also doing framing, electrical and
tile, for example. THEN I can be a plumber.
My original question about unions in gas lines was in some part to evoke a
debate. I also asked the inspectors in the city I am doing work in right
now. Even THEY had different answers. One guy only really has an interest in
life-safety issues and if something works, it works. He'll accept things not
in the code based on if there was really no other way to do it and it isn't
a life-safety issue. A union for him was, in some cases, potentially
acceptable. Another guy said no way, under no circumstances, impossible,
don't even think about it. You read the responses, some yes, some no. I
guess it is enough of a grey area that no one can give a good answer. Some
guys said "Look at a gas meter, there is a union there". Here in California,
the gas utilities also run plastic pipe from a gas main to a meter (wouldn't
I love that). But there is no way I can run plastic gas pipe inside a house.
Some cities won't even let me run corregated stainless steel gas lines (even
though it is in the code) becasuse it takes jobs away from union pipe
fitters.
Different strokes for different folks...

That may be (or 'is') true, but for gas projects you may find that
there are additional (legal) requirements that you must be able to
meet to pass the buiding inspection. My comment is based on this being
a gas line (were it a water line, I'd have not bothered). Just that
most places are *really* sensitive about gas installations! (yep, it's
*almost* impossible to blow up a house by plumbing the crapper wrong!)
<bg>

Your "hybrid" sounds like a mini-tank with tankless heating capacity /
gas usage. Getting the pipe sized correctly is important to heater
performance.
What is the maximum gas consumption of the heater? I'm guessing
something in the 200K btu/hr. Depending on run length and other gas
demand; 3/4" should be fine
Do a proper analysis of your gas piping, considering all your current
& added gas usage...its not that difficult
google natural gas pipe sizing
and choose the third hit
or take a look at 5th hit...its a bit more detailed
Making up a connection via a "left/right" can be a PITA but if you
use GOOD quality teflon tape & a couple extra wraps that will be more
forgiving on the connection. Also, building in some piping compliance
with make the connections easier. Consider CSST which gives you the
benefits of "unions" without the arguments from inspectors....well, if
CSST is allowed in your area.
cheers
Bob

"should be fine" my table shows 1" after 10 ft if I remember it right,
if flow is minimal 1" might be needed for all of it. You can live with
a heating system starved a bit and stay warm, but I dont like cold
showers.

just put the 1/2" line on the water heater. Especially for that short
distance. Sounds like your "T" is within a couple of feet of the
heater. You'd need a dam big heater to require any bigger line. Most
water heaters can be run on a 3/8" line.

"Just Put 1/2" when mnfg says 3/4", no wonder you cant get a tankless
to work, your answer is a hacks answer. Did it ever occure to you his
Hybrid needing 3/4 , needs 3/4" and is probably tankless. The only
Tankless ive seen leave you cold was put in by hacks undersizing the
gas. In reality after checking it with a manometer with competing
apliances on full and calculating winter reductons, he may just need
major meter and line work. Right , just use 1/2", what a joke.

How many Btu is this "hybrid" and whats a Hybrid, is it Tankless? 3/4
gas is a monster commercial tank, My 16 unit apartment tank has 3/4"
gas going to it, so I will assume its a tankless and give you my
experiance on my tankless. If you dont get full required gas flow you
wont get 100% output and will be pissed all winter. Regardless of what
you see in your line size a Manometer must be used to verify gas
supply, some meters may need adjustment or replacing, in winter and
with other apliances on gas flow is reduced and you must figure that
in. In winter my total supply can go down 10-15%, you must plan on
that. 3/4" is recomended, and after so many feet 1" is needed, its
standard and tabled. If its Tankless gas flow must be tested or you
will enter the ranks of "tankless sucks" by guessing and under
supplying it. Sure it may work today, but on the coldest day around
Christmas when every neighbor has every gas apliance running full bore
you may have a cold shower. Manoneters are cheap, and the gas co can
help you on winter pressure reduction estimates. I would not hook to
1/2" anything.

This is a true hybrid. Look up the "Eternal Water Heater". That is it's REAL
name. The Eternal system is a very good heater and puts out something like
26 gallons a minute. My homeowner is getting the larger of the two systems.
Most people have never seen anything like this system.
wrote:

How many Btu is this "hybrid" and whats a Hybrid, is it Tankless? 3/4
gas is a monster commercial tank, My 16 unit apartment tank has 3/4"
gas going to it, so I will assume its a tankless and give you my
experiance on my tankless. If you dont get full required gas flow you
wont get 100% output and will be pissed all winter. Regardless of what
you see in your line size a Manometer must be used to verify gas
supply, some meters may need adjustment or replacing, in winter and
with other apliances on gas flow is reduced and you must figure that
in. In winter my total supply can go down 10-15%, you must plan on
that. 3/4" is recomended, and after so many feet 1" is needed, its
standard and tabled. If its Tankless gas flow must be tested or you
will enter the ranks of "tankless sucks" by guessing and under
supplying it. Sure it may work today, but on the coldest day around
Christmas when every neighbor has every gas apliance running full bore
you may have a cold shower. Manoneters are cheap, and the gas co can
help you on winter pressure reduction estimates. I would not hook to
1/2" anything.

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